Radio antenna



June 13, 1933.

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l. o. BANKS RADIO ANTENNA -Filec 1May l, 1931 9A FAD/0 Ezra m2.

Ira U. Bari/i4,

Patented June 13, 1933 UNITED STATES PATENT OFFICE IRA 0. BANKS, FI-IIGGINSVILLE, MISSOURI, ASSIGN 'OR OF ONE-HALF TO PAULIt. I-IEIDBRINK,OF HIGGINSVILLE, MISSOURI RADIO ANTENNA Application filed May 1, 1931.Serial No. 534,422.

This invention relates to radio antenna and it is an object of theinvention to provide a device for controlling the length of the antennato vary the effective tone and volume of a radio receiving set and tovary the capacity of the outside ground.

Another object of the invention is to provide a device adapted for usewith sets operating on alternating or direct current circuits with thewiring or circuit of the device serving as an indoor antenna for theradio receiver. The device serves as a control for Varying the signalsto the antenna and to vary the potential drop between the ground of the0 set and the antenna post of the set, thus efiectively varying thevolume of the signal received.

Referring to the accompanying drawing, which is made a part hereof andon which similar reference characters indicate similar parts,

Figure 1 is a plan View of the device,

Figure 2, an underside view opposite to that shown in Figure 1, and

Figure 3, a diagrammatic view of the device.

In the drawing numeral indicates the casing in which the parts areenclosed. Mounted upon the casing are posts 11, 12-and 13 to whichsuitable wires 25, 26 and 27 are connected to the radio set antenna postA, to the ground post of the radio set G and to the outside ground Grrespectively. Post 13 is 0 connected by means of a wire 14 to post 15which is in turn connected to an arm 16 having a roller 17 adapted toengage a resistance 18 built in the form of a coil, the ends of theresistance 18 terminating at posts 19 and 20 respectively. A wire 21connects post 20 to to one side of a condenser 23, the other side of thecondenser being connected to post 11 by wire 24.

A shaft 28 on which arm 16 is mounted is provided with a knob 29 on theface of the casing 10 for operating the device.

Numeral 30' indicates an outside antenna and lead-in wire connected tothe antenna post A of the radio set and for use if an outside antenna isdesired to be used with this post 12. Post 19 is connected by a wire 22device. In most cases better results are obtained when the device and anoutdoor antenna are available. e

The operation of the device is as follows: By settingthe knob 29 so thatthe arm 16 carrying the roller 17 is in contact with post 20 a directconnection from the outside ground to the ground of the set is completedwhich substantially reduces the signals coming in on the circuit of thedevice when it is used asan indoor antenna. By connecting the outsideantenna 30 to post A to which lead 25 from post 11 of the device is alsoattached, signals will come in on the outside antenna since all theresistance 18 lies between the ground and antenna posts of the set.

By turning the knob 29 clockwise the roller 17 can be made to divide theresistance 18 into two equal portions. This gives a balancing effect andsignals are now coming in on the outside antenna and the device whichserves as an inside antenna. Signals are now obtained from both indoorand outside antennae. Continuing in the same direction (clockwise) astronger ground is obtained and hence stronger radio signals, whichsignals continue to increase as the knob 29 is rotated to a point wherethe roller 17 contacts with post 19. At this limit the incoming signalsare now obtained through the indoor s antenna (the device) andcontrolled by this device.

At all times the condenser 23 is in line 24 in both cases whethersignals are coming in on the device which serves as an indoor antenna oron the outside antenna. The resistance may vary between the post 13 withrespect to posts 11 and 12; it is always the same between posts 11 and12. No connection is made between post 11 and post 12 since the antennaleads are connected to the condenser 23.

By use of this device it is possible to vary the volume and control byrotation of the knob from one extreme to the other and either, antennamay be used, or both, and controlled by this device which itself servesas the indoor antenna, thereby providing a wide range of control for theradio receiving set and 1 l with such a range it is possible to obtainthe most satisfactory results regardless of atmospheric conditions.

It will be obvious to those skilled in the art that various changes maybe made in my device Without departing from the spirit of the inventionand therefore I do not limit myself to what is shown in the drawing anddescribed in the specification, but only as inclicated by the appendedclaim.

Having thus fully described my said invention, what I claim as new anddesire to secure by Letters Patent, is:

A variable antenna control for a radio receiver having an antenna postand a ground post comprising a resistance and a condenser connected inseries between the antenna post and the ground post of the radioreceiver and a grounded arm rotatably mounted in contact with saidresistance adapted to vary the potentialdrop between said antenna andground posts of the radioreceiver, substantiallyas set forth.

-In witness whereof, I have hereunto set my hand at l-Iigginsville,Missouri, this 27th day of April, A. 1)., nineteen hundred andthirtyone.

IRA 'O. BANKS.

